By 6pm today, more than £20,000 had been pledged in memory of Christian Smith who was killed following the crash which happened at about 4am yesterday.
The fundraiser was involved in the accident involving a blue Peugeot 206 car on the A2990 Old Thanet Way, near Chestfield, Kent, during his bid to circumnavigate the county in aid of the mental health charity MIND.
The 18-year-old female driver of the Peugeot was arrested on suspicion of drink-driving and causing death by dangerous driving and has been released on police bail until July 26.
In his last posting on his JustGiving webpage, Mr Smith, who would have celebrated his 39th birthday next week, wrote: "Oh crap what have I done....6 days to go. Birthday drinks in Kings Head on 29th March if I am still alive by then."
Mr Smith's family said in a statement: "Christian Smith, of Boughton Aulph in Kent, was killed in the early hours of Saturday morning, while cycling to raise money for the MIND charity.
"Christian leaves a loving wife and three children."
Mr Smith had set out on Friday to complete his "Kent Epic" of cycling 248 miles around Kent in 24 hours.
Describing his fundraising bid, he wrote: "This is an attempt to cycle the full 24hrs and the full distance, largely unsupported (because nobody is stupid enough to volunteer!). So there are no motorcycle outriders, support vehicles or hot chicks to wipe my brow.
"As much as this being a physical effort, it will also be a mental struggle, enduring a long dark night alone, knackered. Not to mention the long training sessions ahead of me to prepare."
Explaining his motivation, he added: "In short I want to support the charity MIND, raise awareness towards the great support that they offer, and help bring an end to the stigma that is attached to those who suffer from mental health problems.
"I have had my own misfortune to suffer from a spate of poor mental health, which was unexpected and has been a real 'game changer' in how I now view the future. It has been a tough road to get to this point but I have been fortunate enough to have the support of my family and friends.
"There are those who are not so fortunate to have the same level of support and understanding. They suffer in silence and are alone. This challenge is for those people."
He also posted: "If I get to £1,000 I will cycle naked around Wye!" His total has already reached 20 times this goal.
Pc Jamie Woodhams, of the Kent Police Serious Collision Investigation Unit, said: "We are continuing to appeal for witnesses to come forward. In particular, we would like to speak to anybody who saw the Peugeot travelling along the road prior to the collision."